An Investigation of Optimized Operational Parameters for a

*Corresponding author (N.V. Hung). Tel (mobile): +84-0907913567, Fax: +84-37240020. E-mail addresses: [email protected], [email protected]. 2011. International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies. Volume 2 No.4. ISSN 2228-9860. eISSN 1906-9642. Online Available at http://TuEngr.com/V02/423-436.pdf

423

International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies

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An Investigation of Optimized Operational Parameters for a Chicken Slaughtering System in Vietnam

Nguyen Van Hunga*, Doan Hung Minhb, and Dang Thanh Sonc

a Department of Mechatronics, Faculty of Engineering, Nong Lam University, Ho Chi Minh City, VIET NAM b DongNai Science and Technology Department, VIET NAM c Department of Mechanical Engineering, Faculty of Engineering, Vinh Long University, VIET NAM A R T I C L E I N F O

A B S T RA C T

Article history: Received 17 August 2011 Received in revised form 23 September 2011 Accepted 25 September 2011 Available online 25 September 2011 Keywords: slaughtering, stunning, defeathering, scalding, black box, optimized operational parameters.

A 500 birds/hour chicken slaughtering system with improved designs was used to investigate optimized operational parameters of scalding and defeathering process under chicken characteristics in Vietnam. The experiment is designed based on Orthogonal Second-order Design. Results of analysis of variance presented that scalding temperature and distance between two defeathering bands have had a most significant effect on product quality. The optimal solutions showed that the optimized operation parameters are 1.8 (m3/20birds) in scalding water flow, 67 (0C) in scalding temperature and 80 (seconds) in scalding time for scalding machine; and 415 (mm) in gap between two defeathering bands, 340 (rpm) in defeathering disc velocity and 120 (seconds) in defeathering time for defeathering machine. The implementation results of the lines designed based on these optimized operational parameters have confirmed the appropriateness for the optimization values suggested.

2011 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies.

2011 International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies.

424 Nguyen Van Hung, Doan Hung Minh, and Dang Thanh. Son

Nomenclature

q scalding water flow (m3/bird)

T scalding temperature (oC)

ts scalding time (seconds)

a distance between two deafthering bands (mm)

n defeathering velocity (rpm)

td defeathering time (seconds)

1. Introduction Poultry products and processing in the international market place has been introduced by

Bilgili (2002). In Vietnam, there has been a significant increase in demands of poultry meat in

recent years. According to the General Statistics Office of Vietnam in June 2010, poultry meat

(live weight) gained 330,700 tons and the target for 2020 is 300 million tons of chicken (UN

Food Wire News, 2010). In order to have hygiene meat, the necessary conditions involve in

breeding animals, feed, breeding facilities, and especially appropriate slaughtering systems that

can reduce the risk of virus contamination (e.g. H5N1) and other disease sources.

Over the past decade, some modern poultry slaughtering systems from Linko and Stork

Company have been used quite well in Vietnam. The advantages of these systems are high

productivity and automation. However, these technologies and equipment still have some

disadvantages such as large scale and especially technical parameters that have not been fit to

the chicken conditions (“Tam Hoang” chicken with the average weight of 1.8 kg) in Vietnam

yet.

This paper will present the results of an experimental investigation for technical

parameters in scalding and defeathering process of a 500 birds/hour chicken slaughtering

system for Tam Hoang chicken. The objective of the investigation is to determine the values of

operational parameters that make a certain minimum percentage of the hair weight remained on

the chicken product under condition of skin undamaged. These operation parameters have been

named to be “optimized operational parameters” in this paper.


425

1.1 A chicken slaughtering system 500 birds/hour

This section will introduce a chicken slaughtering system 500 birds/hour with improved

designs. This system has been used for both purposes, producing and experimental

investigating for optimized operational parameters.

Technology and equipment for poultry product has been introduced by Momtney et al.,

(1984) and also by Sams (2001). Analysis and technological rationalization of poultry

processing lines has been described in Hung (2003). Designing a poultry processing line 500

birds/hour for the poultry condition in Vietnam has been published by Hung and Kovac (2003).

Recent research on building small scale models for processing poultry in Vietnam has been

provided by Hung (2006) and Hung (2010). Based on the critical review results and typical

models of the modern poultry processing of Companies Linko and Stork, a 500 birds/hour

chicken slaughtering system was designed, manufactured and installed for producing and

experimental investigation. The schema of this system is shown in Figure 1.

Figure 1: Scheme of the chicken sluaghtering system 500 birds/hour (Hung, 2010).

The system includes the following components: 1. Stunner; 2. The main over head

conveyer; 3. Blooding tray; 4. Scalder; 5. Defeathering machine; 6. Eviscerating tray; 7.

Equipment for sterilizing; and 8. Drying conveyor, in which, the overhead conveyor, stunner,

continuous scalder, disk defeathering machine and sterilizing instruments are the main

components. The most important operations of the poultry slaughtering system are scalding and

defeathering because of their significant effects on the product quality.


The scalding machine was designed based on the parameters of scalding temperature,

water flow and time, shown in Figure 2. The scalding machine includes five main

components: 1. Frame; 2. Hanger; 3. Scalding bin; 4. Chicken; and 5. Water level meter.

The defeathering machine, Figure 3, was designed based on the parameters of the distance

between its two bands, velocity and time of defeathering. These parameters can be controlled

automatically to meet product quality.

Figure 2: Principle of Scalding machine (Hung, 2010).

Figure 3: Principle of defeathering machine (Hung, 2010).

The scalding machine includes the main components: 1: Overhead conveyor, 2: Water

sprayer; 3: Defeathering finger; 4: Motor; 5: Frame; and 6: Hair trough. A chicken

slaughtering line 500 birds/hour installed KhanhHoa province, Vietnam, shown in Figure 4.


427

Figure 4: The chicken slaughtering system 500 birds/hour installed in KhanhHoa province.

This line is offered by Food Company Huong Giang. It is noted that in this line the

operational parameters of stunner, scalding and defeathering machines can be adjusted to

achieve a designed range of the experimental factors.

2. Materials and Methods

This section will present the experimental conditions and methodology for investigating

the relationship between the operational parameters and chicken product quality in a chicken

slaughtering process.

Experiments were conducted on the chicken slaughtering system 500 birds/hour described

in the above section. The tested chicken is the “Tam Hoang” chicken of seven weeks age and

1.8 kg in average weight. The selected interfering factors for chicken feature are constant with

5% in error.

In tests, defeathering velocity was measured by the optical RPM meter, Figure 5a; and

scalding temperature was measured by the Dataloger USB series 006p CMA, Figure 5b. The

product quality was determined by percentage of the hair weight remained on the chicken

product under condition of skin undamaged, shown in Figure 5c.


Figure 5: (a) Measuring defeathering velocity; (b) The datalogger used in measure scalding

temperature; (c) Hair remained on the chicken product.

Investigation of the relationship between the operational parameters and chicken product

quality is based on a “black box” model. In general, the input parameters of black box should

include the operational parameters of three machines of stunning, scalding and defeathering.

However, for stunner, the best operation parameters for Tam Hoang chicken have been

suggested in Hung (2006): type of electric stunning with 1.5 – 1.8 Amperes, 110 – 130 Volts and

1.5 seconds in time amount. Theorefore, here, the input parameters in black box have been

selected as in Figure 6.

Figure 6: A black box model selected for investigation.

In this research, only the scalding and defeathering parameters that significantly affect to

the chicken product quality are selected to be the input parameters described in Figure 6. The

output parameter is chicken product quality that was determined by percentage of the hair

weight remained on the chicken product under the condition of undamaged skin condition. It is

acknowledged that the output parameters should include the economic criteria such as specific

energy consumption. However, some initial tests showed that the effects of the investigated


429

parameters to this criterion are not significant compared with the total slaughtering cost,

therefore, it is neglected.

The experiment is designed based on Orthogonal Second-order Design (Box-Benken

Design) (Zivorad, 2004), in which, the response surface is set up with three factors for each of

process of scalding and defeathering. The total number of tests for each process is 15

(23+2*3+1) and is performed randomly. Analysis of variance (ANOVA) is treated by

Statgrahics 7.0 software. The determined experimental model is an objective function in

optimal problem. The optimization solutions are found based on the constrained gradient

method (Rao, 1985; Hung, 1998) and Matlab software (Hung, 2008).

3. Results and Discussions

In this section, firstly, the experimental results for chicken scalding and defeathering will

be provided. Then, based on the results of ANOVA, the effects of scalding and defeathering

factors to hair remained on chicken product will be presented. Finally, based on the

optimization solutions, the values of the optimized operational parameters of scalding and

defeathering machines will be provided.

For scalding process, the output results corresponding to the input parameters are shown in

Table 1.

Table 1: Experimental results of chicken scalding (Box-Behnken method). Run q

m3/20bird T

(0C) ts

(seconds) Y1 (%) Run q

m3/20bird T

(0C) ts

(seconds) Y1 (%)

1 1.7 64 90 0.1 8 1.7 60 120 4.42 2 2.0 60 90 6.28 9 1.7 68 120 1.42 3 1.4 64 60 3.84 10 1.4 60 90 8.68 4 1.7 64 90 0.16 11 1.7 60 60 9.47 5 1.4 64 120 1.72 12 1.7 68 60 0.2 6 2.0 64 120 0.48 13 2.0 68 90 1.04 7 2.0 64 60 2.3 14 1.4 68 90 1.62 15 1.7 64 90 0.15

In Table 1, q is scalding water flow (m3/20bird, means 20 birds conveyed through the

scalding equipment at any time), T is scalding temperature (0C), and ts is scalding time

(seconds) , and Y1 is percentage of hair weight remained on chicken product affected by these

scalding factors.


For defeathering process, the output results corresponding to the input parameters are

shown in Table 2.

In Table 2, a is distance between two defeathering bands (mm), n is defeathering velocity

(rpm), td is defeathering time, and Y2 is percentage of hair weight remained on chicken product

with the constrained factor of undamaged skin.

Table 2: Experimental results of chicken defeathering (Box-Behnken method).

Run a (mm) n (rpm)

td seconds

Y2 (%) Run a (mm) n

(rpm) td

seconds Y2 (%)

1 485 320 80 15.01 8 415 320 80 9.27 2 450 320 105 9.32 9 485 290 105 14.33 3 450 320 105 9.02 10 415 320 130 1.50 4 450 350 80 8.12 11 485 350 105 13.32 5 485 320 130 16.52 12 415 290 105 7.23 6 450 290 80 9.52 13 450 290 130 8.63 7 415 350 105 2.30 14 450 350 130 6.45 15 450 320 105 9.89

(a) (b)

(c) (d)

Figure 7: (a) Pareto Chart for hair remained affected by scalding parameters

(b), (c), (d). Respone surfaces of the dependence of hair remained affected by scalding

parameters.

X1-axis, scalding water flow, m3/10birds

X2-a

xis,

Sca

ldin

g te

mp.

, deg

C

Percentage of hair remained on chicken product, %

1.4 1.5 1.6 1.7 1.8 1.9 260

61

62

63

64

65

66

67

68

0

1

2

3

4

5

6

7

8

X1-axis, scalding water flow, m3/10birds

X3-a

xis,

Sca

ldin

g tim

e, s

econ

ds


1.4 1.5 1.6 1.7 1.8 1.9 260

70

80

90

100

110

120

1.5

2

2.5

3

3.5

4

4.5

5

X2-axis, scalding temp., degC

X3-a

xis,

Sca

ldin

g tim

e, s

econ

ds


60 61 62 63 64 65 66 67 6860

70

80

90

100

110

120

1

2

3

4

5

6

7

8

9

10


431

The experimental data was treated by ANOVA detailed in Appendices 1 and 2. After

eliminating the unreliable coefficients and checking the conformability, the regression

equations and of scalding and defeathering process; and response surfaces of the investigation

are drawn.

For scalding process, the effects of scalding water flow (q), temperatue (T) and time (ts) to

percentage of hair weight remained on chicken product (Y1) can be described by the following

equation (1) and Figure 7a.

Y1 = 995.97 – 74.1824*q – 26.8314*T – 1.02463*? + 13.7546*q2 + 0.379167*q*T +

0.00833333*q* ts + 0.189401*T2 + 0.0130625*T* ts + 0.000789352* ts 2 (1)

The response surfaces of the investigation can be described in Figures 7.b, c, and d.

In Figure 7, factors X1, X2 and X3 are the scalding water flow, scalding temperature and

scalding time, respectively. Figure 7.a showed influence level of scalding factors on product

quality in a designed value range for the operation parameters. The scalding temperature has

had a strongest effect to product quality; the next are scalding time and scalding water flow in

order. It is noted that product quality is in inverse relationship to scalding temperature. Figures

7.b, c and d, showed that in range of 1,6 – 2 (m3/20birds) of scalding water flow, 65 – 68 (0C)

of scalding temperature and 90 – 120 (seconds) of scalding time, percentage of hair weight

remained on chicken product after defeathering is less than 2% and undamaged skin.

For defeathering process, the effects of defeathering velocity (n), time (td) and distance

between two defeathering bands (a) to percentage of hair weight remained on chicken product

(Y2) can be described by the following equation (2) and Figure 8(a).

Y2 = 269.065 – 1.27435*a + 0.434145*n - 1.23724* td + 0.000933333*a*n +

0.000265143*a* td + 0.0000929042*a2 – 0.000139658*n2 (2)

The response surfaces of this investigation can be described in Figures 8(b),(c), and (d).


(a) (b)

(c) (d)

Figure 8: (a) Pareto Chart for hair remained affected by defeathering parameters

(b), (c), (d). Respone surfaces of the dependence of hair remained affected by defeathering

parameters.

In Figure 8, factors X1, X2 and X3 are the distance between two defeathering bands, defeathering disc velocity and defeathering time, respectively. Figure 7.a showed influence level of defeathering factors on product quality in a designed value range for the operation parameters. The effect of the X1 on product quality is much more significant than that of the X2 and X3. Figures 8.b, c and d, showed that in range of 415 - 430 (mm) of the gap between two defeathering bands (included length of defeathering finger), 340 – 350 (rpm) of defeathering disc velocity and 120 – 130 (seconds) of defeathering time, percentage of hair weight remained on chicken product is less than 2% and undamaged skin.

In order to meet the chicken product quality required by requirement of chicken product

market (percentage of hair weight remained on chicken product under 95% and undamaged

skin), the appropriate values and values optimized operational parameters of the scalding and

defeathering machines are shown in Table 3.

X1-axis, distance - two bands, mm

X2-a

xis,

def

eath

. dis

k ve

loci

ty, r

pm


420 430 440 450 460 470290

300

310

320

330

340

350

3

4

5

6

7

8

9

10

11

12

13

X1-axis, distance - two bands, mm

X3-a

xis,

def

eath

erin

g tim

e, s

econ

ds


420 430 440 450 460 47080

85

90

95

100

105

110

115

120

125

3

4

5

6

7

8

9

10

11

12

13

X2-axis, defeathering disk velocity, rpm

X3-a

xis,

def

eath

erin

g tim

e, s

econ

ds


290 300 310 320 330 340 35080

85

90

95

100

105

110

115

120

125

7

7.5

8

8.5

9

9.5

10

10.5

11


433

A practical evaluation for the values provided in Table 3 showed that the product quality

satisfied the required criteria.

Table 3: The operation parameters of the scalding and defeathering machines for Tam Hoang

chicken.

Parameters Unit Appropriate value

Optimized value

Scalding water flow m3/20bird 1.6 ÷2 1.8 Scalding temperature 0C 65÷68 67 Scalding time seconds 80÷120 80 Distance between two deafthering bands (length of defeathering finger 200mm) mm 415÷430 415

Defeathering velocity rpm 340÷350 340 Defeathering time seconds 120÷130 120

The values of optimized operational parameters have been used to design a new chicken

slaughtering system 500 birds/hour. This line was offered by Celin Thai Company, Binh Thuan

Province. The product quality from this line has reconfirmed the appropriateness for the values

of optimized operational paramaters suggested. Furthermore, the project of chicken

slaughtering line 500 birds/hour has been awarded a Vietnamese prize of science and

technology.

4. Conclusions An experimental investigation for optimized operational parameters of scalding and

defeathering process for Tam Hoang chicken was conducted on a chicken slaughtering line 500

birds/hour. Design of experiments was based Box-Benken method. ANOVA was performed

to evaluate effects of the operation parametes on product quality. Results presented that

scalding temperature and distance between two defeathering bands have had a most significant

effect on product quality. The optimal solution based on constrained gradient provided the

values optimized operation parameters: 1,8 (m3/20birds) in scalding water flow, 67 (0C) in

scalding temperature and 80 (seconds) in scalding time for scalding machine; and 415 (mm) in

the gap between two defeathering bands (included length of defeathering finger), 340 (rpm) in

defeathering disc velocity and 120 (seconds) in defeathering time for defeathering machine.


A practical evaluation for the optimization values was performed. Results showed that the

product quality is to meet the required criteria (percentage of hair weight remained on chicken

product under 95% and undamaged skin). The stable operation and product quality of the lines

which were designed based on the optimized operation parameters have confirmed the

appropriateness for the values suggested.

The values of operation parameters suggested for chicken slaughtering line 500 birds/hour

seems to be fit to the scale of line of under 1000 birds/hour. An analysis and technological

rationalization for many different scales have being investigated.

5. Acknowledgements

The authors are grateful for the support of the Center for Energy and Agricultural

Machinery, Nonglam university and LeKhoa private Enterprise in manufacture of the system.

A very special thank you is due to Assistant Professor Dr. Sawat Pararach for insightful

comments, helping clarify and improve the manuscript.

6. References Bilgili, S.F. 2002. Poultry products and processing in the international market place. Auburn

University, AL 36849-5416, 56 pages.

Hung, N.V. and Kovac, S. 2003. Design of poultry processing line 500 birds per hour for Vietnam condition. In: III. International Young Scientist conference. Praha : CZU. p 100-105.

Hung, N. V. 2003. Analysis and technological rationalization of poultry processing lines. Ph.D thesis. University of Agriculture in Nitra, Slovakia. 170 pages.

Hung, N.V. 2006. Reseach on Improving of small scale systems of poultry processing in Hochiminh city (in Vietnamese). Summary Report of the Project supported by Ministry of Education and Training. 84 pages.

Hung, N.V. 2008. Numerical methods and Applied Matlab in Engineering (in Vietnamese). Vietnamese Agricultural Publishing House. 150 pages.

Hung, N.V. 2010. Reseach on improving techonology and equipment of small scale poultry slaughtering systems under chicken characteristics in Vietnam (in Vietnamese). Summary Report of the Project supported by Ministry of Education and Training. 120 pages.


435

Momtney, G.J. – Carmen, R. – ParkHusrst, L. 1984. Poultry products technology. Third Edition, Food Products Press, New York, 446 pages.

Rao, SS. 1985. Optimization – Theory and Apllication. New Age International (P) Limited, Publishers Wiley Eastern Limited, 739 pages.

Sams, A.R. 2001. Poultry meat processing. Boca Raton CRS Press. 334 pages.

Zivorad R. L. 2004. Design of Experiments in Chemical Engineering. WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim (ISBN: 3-527-31142-4), page 351-356.

UN Food and Agriculture Organization; General Statistics Office of Vietnam. 2010; World Bank; OIE; CIA World Factbook; FAPRI; news wires: July 2010. (www.meattradenewsdaily.co.uk/news/210710/vietnam___poultry_farming_on_the_rise_.aspx Accessed: August 2011).

Appendices

Appendix 1:

Result of Analysis of Variance for percentage of hair weight remained on chicken product

affected by scalding parameters ------------------------------------------------------------------------------- Source Sum of Squares Df Mean Square F-Ratio P-Value ------------------------------------------------------------------------------- A:Water flow 4.1472 1 4.1472 4013.42 0.0002 B:Temperature 75.4606 1 75.4606 73026.40 0.0000 C:Scald.Time 7.54661 1 7.54661 7303.17 0.0001 AA 5.65823 1 5.65823 5475.71 0.0002 AB 0.8281 1 0.8281 801.39 0.0012 AC 0.0225 1 0.0225 21.77 0.0430 BB 33.908 1 33.908 32814.22 0.0000 BC 9.82823 1 9.82823 9511.19 0.0001 CC 1.86348 1 1.86348 1803.37 0.0006 Lack-of-fit 0.006625 3 0.00220833 2.14 0.3345 Pure error 0.00206667 2 0.00103333 -------------------------------------------------------------------------------- Total (corr.) 136.114 14 R-squared (adjusted for d.f.) = 99.9821 percent


Appendix 2:

Result of Analysis of Variance for percentage of hair weight remained on chicken product

affected by defeathering parameters ------------------------------------------------------------------------- Source Sum of Squares DF Mean Square F-Ratio P-value ------------------------------------------------------------------------- A:Distance between 188.95680 1 188.95680 967.52 .0010 two defeath.bands B:Defeath.velocity 11.32880 1 11.32880 58.01 .0168 C:Defeath.Time 9.72405 1 9.72405 49.79 .0195 AB 3.84160 1 3.84160 19.67 .0473 AC 21.52960 1 21.52960 110.24 .0089 AA 4.81081 1 4.81081 24.63 .0383 BB 5.86804 1 5.86804 30.05 .0317 Lack-of-fit 3.43306 5 .68661 3.52 .2362 Pure error .39060 2 .19530 ------------------------------------------------------------------------- Total (corr.) 250.701040 14 R-squared (adj. for d.f.) = 0.969496

Dr.Nguyen Van Hung received his doctoral degree in Mechanical Engineering from Slovak University of Agriculture in Nitra, Slovakia Republic. He is now Vice Dean of the Faculty of Engineering, and Head of Department of Mechatronics, Nong Lam University, Vietnam. His research is focused on Agricultural Engineering, especially pertinent to improvement of agricultural process and machinery.

Doan Hung Minh received his Master of Science degree in Mechanical Engineering. He is Deputy Head of Applied Research Unit – DongNai Science and Technology Department, Vietnam.

Dang Thanh Son received his MSc in Mechanical Engineering. He is lecturer at Vinh Long University, Vietnam.

Peer Review: This article has been internationally peer-reviewed and accepted for publication

according to the guidelines given at the journal’s website.

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An Investigation of Optimized Operational Parameters for a